Lev. 26:1-2 looks like a very condensed summary of the covenant: don’t do that (v.1); do this (v.2). We might wonder: why summarize the covenant this way? (How else could it have been summarized?)
What, for that matter, is wrong with idols, images, etc.? The answer is clear if the image is intended to point to any god except the LORD. By our numbering that’s covered in the first commandment; images per se, a separate issue (the second commandment). Different texts may point to different answers. I wonder if it doesn’t go back to Gen 1:26-27. If you want an image of God, pay attention to human beings; experience suggests that any other image leads to human beings being treated in inhuman ways.
“You shall keep my sabbaths and reverence my sanctuary.” The one organizes time (every 7th day, every 7th year, every 7x 7th year—recall Lev. 25); the other organizes space (the tabernacle/temple itself, the land of Israel, other lands; different gifts flow in different directions). How do we Christians understand the New Covenant to organize our time, our space?
Lev. 26:3-39 describes the blessings obedience brings and the curses disobedience brings, a standard element in the ancient near eastern treaties that served as a rough template for the Mosaic covenant. Among the many things we might wonder about, here are two. In vv.3-13 economic prosperity and national security are byproducts of the nation’s conduct before God. We tend to treat them as goods to be pursued directly.
Second, the whole obedience-brings-blessing-disobedience-brings-curse paradigm. On the one hand, does any part of the Bible remain intact if the paradigm is discarded? On the other hand, multiple voices within the OT warn us to use it with extreme caution. In 2 Kings righteous king Josiah dies young and wicked king Manasseh lives to a ripe old age. Job exhibits at length the disastrous results of using the paradigm diagnostically (Job is suffering, so Job is a sinner). What do we do with it?